Liquefied air refrigeration system for storage container

ABSTRACT

A liquid refrigeration system for a thermally-insulated storage container includes a tank configured to store liquid air therein, a conduit system having a first end portion coupled to the tank and a second end portion configured to be positioned within an interior of the thermally-insulated storage container, a spray head coupled to the second end portion of the conduit system, a control system electrically coupled to the tank and the spray head to control the flow of liquid air from the tank to the spray head.

This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/318,607 entitled LIQUEFIED AIR REFRIGERATION SYSTEM FOR STORAGE CONTAINER, the entirety of which is hereby incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to storage containers, such as static or mobile storage containers. In particular, the present invention relates to a refrigeration system for thermally insulated static or mobile storage containers.

BACKGROUND

Many storage containers, including both static and mobile storage containers, are thermally insulated in order to allow the container to be cooled or refrigerated. Such insulated containers are frequently used for the storage and preservation of products such as food stuffs and biological materials, for example, requiring low or sub zero temperatures. Oftentimes, such low temperatures are achieved through the use of electrical or engine driven refrigeration systems. Alternatively, liquid cryogenic gasses in both direct and indirect applications maybe used as well.

Cryogenic gas refrigeration systems typically use carbon dioxide, nitrogen, or other non-breathable gases as the refrigerant. However, these gases, in the concentrations achieved in the direct application systems in which the cold gas is introduced directly into the container result in depletion of oxygen levels below that required to support human life. Therefore, and prior to entry to the container, the gasses must either be vented or the entrant must wear a breathing apparatus. Furthermore, the container is typically also equipped with devices to monitor the oxygen level. Such devices may operate to provide a warning of inadequacy for sustainment of life and/or to provide a barrier to entry into the container in the event of lower than life sustaining oxygen levels. Other cryogenic gas refrigeration systems for medical imaging and particle physics, for example, may use liquid helium in order to achieve super cold temperatures.

Alternatively, indirect cryogenic refrigerant systems operate such that the refrigerant gasses are circulated through a heat exchanger and do not directly enter the container. However, in the event of a heat exchanger failure, such systems may also present an asphyxiation hazard which needs to be protected against.

SUMMARY

The present invention may comprise one or more of the features recited in the attached claims, and/or one or more of the following features and combinations thereof.

According to one aspect of the present disclosure a liquid air refrigeration system for a thermally-insulated storage container includes a tank configured to store liquid air therein, a conduit system having a first end portion coupled to the tank and a second end portion configured to be positioned within an interior of the thermally-insulated storage container, a spray head coupled to the second end portion of the conduit system, and a control system electrically coupled to the tank and the spray head to control the flow of liquid air from the tank to the spray head.

In one illustrative embodiment, the liquid refrigeration system may further include another spray head coupled to the second end portion of the conduit system.

In another illustrative embodiment, the liquid refrigeration system may further include an evaporator coupled to the tank and the conduit system. Illustratively, the evaporator may operate to convert the liquid air to a gaseous state.

In still another illustrative embodiment, the liquid refrigeration system may further include a temperature sensor configured to be positioned within the interior of the thermally-insulated storage container. Illustratively, the temperature sensor may be configured to monitor the temperature within the interior of the thermally-insulated storage container. Further illustratively, the temperature sensor may be electrically coupled to the control system such that the control system may be configured to adjust the rate of flow of the liquid air from the liquid air tank based upon the temperature sensed by the temperature sensor. Continuing, the tank may include an inlet port, and inlet valve within the inlet port, an outlet port, and an outlet valve within the outlet port. Illustratively, the inlet valve and outlet valve may each be electrically coupled to the control system such that the control system may be configured to open and close the outlet valve to adjust the rate of flow of the liquid air from the liquid air tank.

In another illustrative embodiment, the liquid refrigeration system may further include a second tank configured to store liquid air therein. Illustratively, the second tank may be coupled to the conduit system.

In still another illustrative embodiment, the liquid refrigeration system may further include a flow rate sensor configured to sense the flow rate of the liquid air within the conduit system. Illustratively, the flow rate sensor may be electrically coupled to the control system such that control system may be configured to adjust the rate of flow of the liquid air from the liquid air tank based upon the flow rate sensed by the flow rate sensor.

According to another aspect of the present disclosure, a refrigerated storage trailer includes a thermally-insulated container and a liquid air refrigeration system coupled to the thermally-insulated container to supply liquid air to an interior of the thermally-insulated container.

In one illustrative embodiment, the liquid air refrigeration system may include a tank configured to store liquid air therein, and a conduit system having a first end portion coupled to the tank and a second end portion positioned within the interior of the thermally-insulated storage container. The conduit system may include a plurality of valves configured to control the flow of the liquid air from the tank to the thermally-insulated compartment.

Further illustratively, the liquid air refrigeration system may also include a plurality of spray heads coupled to the second end portion of the conduit system. The refrigerated storage trailer may also include a control system electrically coupled to liquid air refrigeration system to control the flow rate of liquid air into the interior of the thermally-insulated container. Illustratively, the refrigerated storage trailer may also include a temperature sensor positioned within the interior of the thermally-insulated storage container. The temperature sensor may be configured to monitor the temperature within the thermally-insulated storage container and may be electrically coupled to the control system such that the control system may adjust the rate of flow of the liquid air from the liquid air tank based upon the temperature sensed by the temperature sensor.

In another illustrative embodiment, the refrigerated storage trailer may also include a plurality of flow rate sensors configured to measure the rate of flow of the liquid air through the conduit system.

According to still another aspect of the present disclosure, a method of refrigerating a storage container includes providing a source of pressurized liquid air, injecting the liquid air from the source through a spray head into the storage container, and controlling the flow rate of the liquid air from the source.

In one illustrative embodiment, controlling the flow rate may include monitoring a temperature of an interior of the storage container and adjusting the flow rate of the liquid air from the source based on the monitored temperature.

In another illustrative embodiment, controlling the flow rate may include monitoring the flow rate of liquid air from the source and adjusting the flow rate of the liquid air from the source based on the monitored flow rate.

In still another illustrative embodiment, the method may further include determining if the temperature within the storage container is within a predetermined temperature range and generating a flow rate control signal in response thereto. Illustratively, the method may further include changing the flow rate of the liquid air from the source in response to the flow rate control signal.

According to yet another aspect of the present disclosure, a liquid air refrigeration system for a thermally-insulated storage container includes a liquid air refrigeration system, and a liquid air control system electrically coupled to the liquid air refrigeration system. The control system includes (i) a processing unit, and (ii) a memory unit electrically coupled to the processing unit. Illustratively, the memory unit has a plurality of instructions stored therein, which, when executed by the processing unit, causes the processing unit to: (a) operate the liquid air refrigeration system so as to advance liquid air from a liquid air storage tank to a thermally-insulated interior of a trailer, (b) determine if the temperature within the thermally-insulated interior of the trailer is within a predetermined temperature range and generating a flow rate signal in response thereto, and (c) change the flow rate of the liquid air from the liquid air storage tank to the thermally-insulated interior of the trailer in response to the flow rate signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a container including a liquid air refrigeration system.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to a number of illustrative embodiments shown in the attached drawings and specific language will be used to describe the same. While the concepts of this disclosure are described in relation to a mobile storage container, it will be understood that they are equally applicable to other storage containers generally, and more specifically to conventional box or van type trailers, examples of which include, but should not be limited to, straight truck bodies, small personal and/or commercial trailers and the like.

Referring now to FIG. 1, a liquid air refrigeration system 10 is provided for use with a storage container 12. Illustratively, the storage container 12 may be a static or mobile thermally insulated container. In particular, the storage container 12 may be an insulated trailer configured to be coupled with a truck, or tractor, for storing and transporting various goods therein in a refrigerated atmosphere. Such a refrigerated trailer may include a front wall, opposite side walls, a roof, and an end wall including one or more doors which may collectively cooperate to define a cargo area for storing refrigerated items therein. The opposite side walls may be thermally insulated an dmay include inner and outer aluminum side walls having aluminum posts and foam insulation therebetween. Alternatively, the side walls of such a trailer may be formed of an inner fiberglass skin, and outer fiberglass skin, and a thermoset plastic core, such as that described in U.S. Pat. No. 6,505,883, for example, the entirety of which is incorporated by reference herein. While the storage container 12 may be a trailer or may form a portion of a trailer configured to be coupled with a tractor, it should be understood that the storage container may also form a portion of another refrigerated vehicle such as a van having an insulated storage container, for example.

Of course, it is within the scope of this disclosure for the storage container to be any suitable static or mobile thermally insulated storage container capable of storing goods therein in a refrigerated, or sub-zero (i.e., below 0° C.), atmosphere. It should be understood that the liquid air refrigeration system 10 is capable of maintaining a cooled atmosphere within the storage container 12 at any desired temperature.

As noted in greater detail below, the liquid air refrigeration system 10 uses liquid air to cool the interior 14 of the thermally-insulated portion or compartment of the storage container 12 to sub-zero, or other desired, temperatures. Illustratively, the liquid air refrigeration system 12 uses cooled liquid air in order to refrigerate the interior 14 of the storage container 12. Illustratively, liquid air is air that has been compressed and cooled to very low temperatures such that it has been condensed into a liquid. Liquid air is oftentimes used as a source of nitrogen, oxygen, argon, and other inert gases. In particular, liquid air may be fractioned into its constituent gasses in liquid or gaseous form through an air separation plant. The production of liquid air is oftentimes used commercially as an intermediate step in an air separation process, i.e., the production of nitrogen, oxygen, and argon and other inert gases. Air separation plants produce the atmospheric industrial gases nitrogen, oxygen, and argon.

As noted above, the container 12 is thermally insulated. As such, the container may include an inner and outer skin (not shown) forming the top, bottom, end, and/or sidewalls of the thermally-insulated portion of the container. An insulation layer (not shown) is provided between the inner and outer skins.

Illustratively, the liquid air refrigeration system 10 includes a liquid air tank 16 configured to store liquid air therein. The liquid air tank 16 is thermally-insulated and/or vacuum-insulated in order to maintain the liquid air therein at a sufficiently low temperature. In other words, the liquid air tank 16 stores the liquid air under pressure in a thermally insulated environment. The liquid air tank 16 may include an inlet port 40 configured to receive cooled liquid air therethrough in order to fill the liquid air tank 16 and an outlet port 42 also configured to pass liquid air therethrough. Illustratively, the liquid air tank 16 may include more than one outlet port, such as the second outlet port 44 schematically shown with the inlet and first outlet ports 40, 42 in FIG. 1. The liquid air tank 16 may also include additional outlet ports (not shown). The liquid air tank 16 may be stored outside the storage container 12 or simply outside the thermally-insulated portion of the storage container 12. The liquid air tank 16 may also be coupled to the storage container 12. For example, the liquid air tank 16 may be mounted below a flooring system of the storage container 12 and/or may be coupled to one or more of the side walls of the storage container 12.

The liquid air tank 16 further includes a valve system 17 to control the flow of the liquid gas out the exit port(s) 42, 44, with respect to the demand. In particular, the valve system 17 includes an outlet valve 52 within the outlet port 42, an outlet valve 54 within the outlet port 44, and an inlet valve 50 within the inlet port 40. It should be understood, however, that the liquid air tank 16 may include additional valves as part of the valve system 17. As is discussed in greater detail below, a control system 24 of the liquid air refrigeration system 10 is electrically coupled to the valve system 17 in order to control the opening and closing of the valves to control the flow of the liquid air from the tank 16. It should be understood that the term electrically coupled may refer to wired and wireless electrical connections between components. Further illustratively, the liquid air refrigeration system 10 may include additional valves (not shown) within a conduit system 20 described below, in order to control the flow of the liquid air from the tank 16 to the interior 14 of the storage container 10. Illustratively, the control system 24 includes a processing unit 19 and a memory unit 21 electrically coupled to the processing unit 19. Illustratively, the memory unit 21 has a plurality of instructions stored therein, which, when executed by the processing unit 19, causes the processing unit 19 to operate various components of the liquid air refrigeration system 10 so as to advance liquid air from the storage tank 16 to the interior of the container 12. Power sources for the control system 24 may include battery, power-hook-up to a motive power source such as a tractor, power-hook-up to a ground based supply, or any combination thereof.

The liquid air tank 16 may also include pressure and/or temperature sensors 23 and a microcontroller (not shown) for protecting against excessive pressure build-up in order to ensure that the liquid air tank 16 is in compliance with various rules, standards, and regulations governing such devices. Additional sensor(s) (not shown) may be provided within the tank 16 to monitor the amount of liquid air within the tank 16. Thus, the control system 24, being in electrical communication with such sensor(s), may provide an alert, warning, or other such alarm when the amount of liquid air with the tank 16 drops below a preset threshold level to alert the user of the need to refill the tank 16. While only one liquid air tank 16 is shown, it should be understood that the liquid air refrigeration system 10 may include any number of liquid air tanks 16 for storing liquid air therein. Such additional liquid air tanks 16 may be coupled to the liquid air tank 16 in order to fill the liquid air tank 16 as it is emptied and/or the additional liquid air tanks may be coupled directly to an evaporator 18 and/or in electrical communication with the control system 24. Such additional liquid air tanks may operate independently of the liquid air tank 16 or may operate with the liquid air tank 16 such that multiple liquid air tanks are used simultaneously to cool the interior 14 of the trailer 12.

As noted above, the liquid air refrigeration system 10 further includes a conduit system 20 having a first end portion 25 coupled to the outlet port of the tank 16 and a second end portion 27 located within the interior 14 of the thermally-insulated portion of the storage container 12. Illustratively, as shown in FIG. 1, a plurality of spray heads 22 are coupled to and depend downwardly from the second end portion of the conduit 20. While three spray heads 22 are illustratively shown in FIG. 1, it should be understood that any suitable number of spray heads 22 may be used depending on the size and configuration of the storage container. Further, while the schematic view of the liquid air refrigeration system shown in FIG. 1 illustrates a single feed line (i.e., the second end portion 27 of the conduit 20) within the container 12, it should be understood that any number of interconnected conduits and subconduits may be provided. In other words, the conduit system 20 may include an array of pipes and feed lines within the container 12 in order to evenly distribute the liquid air throughout the interior 14 of the insulated portion of the storage container 12. As noted above, the valve system 17 may include valves (not shown) which are provided throughout the conduit system 20 and at each spray head 22 in order to control the flow of the liquid air selectively to one or more spray heads 22.

As noted above, the control system 24 is in electrical communication with the liquid air tank 14 and the conduit system 20, as well as with various other components of the system 10 including, but not limited to, the valve system 17 and pressure and temperature sensors 23 of the tank 16 as well as one or more temperature sensors 31 mounted within the interior 14 of the thermally-insulated portion of the container 12, for example. Illustratively, the temperatures sensors 31 may be provided within one or more regions of the interior 14 of the storage container 12 in order to detect temperatures of each of these regions. The temperature sensors 31 may be mounted to the side walls, front wall, rear wall and doors, and/or the flooring system of the storage container 12. Illustratively, the control system 24 operates to control and maintain the temperature of the liquid air tank 16 and to control and maintain the desired output of liquid air from the tank 16 to the conduit system 20. In particular, the control system 24 is incorporated to provide modulation of the liquid air fluid flow in accordance with the demands of pre-set temperature requirements of the interior 14 of the thermally-insulated container 12. The fluid flow is also monitored by the control system 24 through the use of one or more thermocouples or other flow rate sensors 60 mounted within the conduit system 20 of the liquid air refrigeration system 10. Illustratively, the flow rate sensors 60 may be positioned at any suitable location within the conduit system 20. For example, the flow rate sensors 60 may be positioned at the first end portion 25 of the conduit system 20 or within the second end portion 27 of the conduit system 27 within the storage container 12. Further, the flow rate sensors 60 may also be positioned within or near the spray heads 22 of the conduit system 20. The control system 24 may further be programmed to stop fluid flow to the spray heads 22 (by controlling the valve system 17 of the tank 16, for example) when access doors (not shown) of the container 12 are opened and remain in an opened position. The conduit system 20 and/or the spray heads 22 may further include a plurality of valves (not shown) in electrical communication with the control system 24 for controlling and regulating fluid flow through the conduit system 20 and into the container 12. The control system 24 further operates to provide a system performance monitoring and data logging function. The control system 24 further operates to provide for alarm outputs in the event of any system malfunction. For example, the control system 24 may telemetrically control an audible and/or visible alarm for alerting users of one or more system malfunctions. The control system 24 may also include a display screen and input device to allow an operator to monitor and change system parameters such as the flow rate of the liquid air from the tank 16 and/or the desired temperature range within the thermally-insulated interior 14 of the container 12, for example.

In operation, the control system 24 operates to generate a gas pressure or flow rate signal through the conduit system 20 responsive to a temperature signal received from one or more temperature sensors 31 mounted within the container 12. The control system 24 regulates the gas pressure in the conduit system 20 when a temperature above or below a preset or predetermined temperature range is sensed within the container 12. In other words, the control system 24 operates to determine if the temperature within the storage container 12 is within the predetermined temperature range, and then operates to generate a flow rate control signal in response thereto. As such, the control system 24 operates to adjust the flow rate of the liquid air from the tank 16 in response to the flow rate control signal by adjusting the valve system 17 of the tank 16, As such, the temperature sensors 31 installed in the interior 14 of the container 12 monitor the temperature within the container 12 and provide this feedback to the control system 24 such that the control system 24 may control the flow rate of the liquid air from the tank 16 into the conduit system 20 and thereby maintain the refrigeration process in control with respect to the predetermined temperature limits.

The liquid air refrigeration system 10 may also include an evaporator tank 18 coupled to the outlet port of the liquid air tank 16. Illustratively, the evaporator tank 18 is configured to change the liquid air from a liquid state to a gas state such that cooled gaseous air 33 is dispensed from the spray heads 22. As such, the liquid air within the tank 16 may be delivered to the thermally-insulated portion 14 of the container 12 as a gaseous spray following passage through the evaporator 18. Alternatively, when the system 10 does not include an evaporator tank 18, the liquid air is delivered in a liquid phase thus creating a droplet spray from the spray heads 22. While the evaporator tank 18 is shown to be located outside the thermally-insulated interior portion 14 of the storage container 12, it should be understood that the evaporator tank 18 may be positioned within the interior 14 of the thermally-insulated portion of the container 12. The control system 24 is also in electrical communication with the evaporator tank 18.

In operation, liquid air from the tank 16 is advanced through the conduit system 20 to the interior 14 of the insulated portion of the storage container 12 in order to refrigerate the interior 14 of the container 12. As shown in FIG. 1, the liquid air is transported from the liquid air tank 16 through the conduit system 20 to exit into the interior 14 of the container 12 via the spray heads 22. The liquid air will emerge from the spray heads 22 as either a droplet spray or as a cold gas 33 (depending on whether the liquid air passed through an evaporator, such as the evaporator 18, or not) in order to chill the interior 14 of the thermally insulated container 12. Illustratively, the liquid air refrigeration system 10 may include one or more heat exchanger systems (not shown) located within the conduit system 20 at or near the spray heads 22 to ensure conversion of the fluid liquid air to a gaseous state prior to emergence from the spray heads 22. Such a heat exchanger system may include one or more sensors located within the pipes at or near the spray heads 22 as well as a microprocessor and controller electrically coupled to the sensors. Illustratively, the sensors may be electrically coupled to the control system 24. In the event that one or more sensors senses liquid air which has not been converted to the gaseous state, the controller 24 may be programmed to halt operation of the refrigeration system 10 and to turn off the spray heads 22 to prevent or minimize any liquid (non gaseous) air from exiting the spray heads 22 into the interior 14 of the thermally-insulated container 12.

Illustratively, the gaseous form of the liquid air is breathable and, therefore, allows for immediate entry into the refrigerated area without the need for time consuming gas evacuation of any non-breathable cryogenic gasses, such as carbon dioxide or nitrogen, or other non-breathable cryogenic gas products. The use of such a breathable refrigerant also eliminates the need for verification of a safe oxygen level within the interior 14 of the container 12 prior to allowing entry to the container 12. In other words, the use of liquid air over other zero oxygen or low oxygen cryogenic liquid gasses is that the atmosphere within the container 12 will remain breathable and, although cold, conducive to the support of human life. Thus, oxygen monitoring systems, vent systems to vent the asphyxiate gasses and/or breathing apparatuses are not required for the safe use of the liquid air refrigeration system 10. Further, elimination of the need to vent asphyxiate gasses may also reduce operating costs due to mitigation of the need to recharge the container's atmosphere after personnel ingress and egress.

While the invention has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as illustrative and not restrictive in character, it being understood that only illustrative embodiments thereof have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. 

1. A liquid air refrigeration system for a thermally-insulated storage container comprising: a tank configured to store liquid air therein; a conduit system having a first end portion coupled to the tank and a second end portion configured to be positioned within an interior of the thermally-insulated storage container; a spray head coupled to the second end of the conduit system; and a control system electrically coupled to the tank and the spray head to control the flow of liquid air from the tank to the spray head.
 2. The liquid refrigeration system of claim 1, further comprising another spray head coupled to the second end portion of the conduit system.
 3. The liquid refrigeration system of claim 1, further comprising an evaporator coupled to the tank and the conduit system and provided to convert the liquid air to a gaseous state.
 4. The liquid refrigeration system of claim 1, further comprising a temperature sensor configured to be positioned within the interior of the thermally-insulated storage container, the temperature sensor configured to monitor the temperature within the interior of the thermally-insulated storage container.
 5. The liquid refrigeration system of claim 4, wherein the temperature sensor is electrically coupled to the control system, and wherein the control system is configured to adjust the rate of flow of the liquid air from the liquid air tank based upon the temperature sensed by the temperature sensor.
 6. The liquid refrigeration system of claim 5, wherein the tank includes an inlet port, and inlet valve within the inlet port, an outlet port, and an outlet valve within the outlet port, and further wherein the inlet valve and outlet valve are each electrically coupled to the control system such that the control system is configured to open and close the outlet valve to adjust the rate of flow of the liquid air from the liquid air tank.
 7. The liquid refrigeration system of claim 1, further comprising a second tank configured to store liquid air therein, the second tank being coupled to the conduit system.
 8. The liquid refrigeration system of claim 1, further comprising a flow rate sensor configured to sense the flow rate of the liquid air within the conduit system.
 9. The liquid refrigeration system of claim 8, wherein the flow rate sensor is electrically coupled to the control system, and wherein the control system is configured to adjust the rate of flow of the liquid air from the liquid air tank based upon the flow rate sensed by the flow rate sensor.
 10. A refrigerated storage trailer for transporting refrigerated cargo comprising: a thermally-insulated storage container; and a liquid air refrigeration system coupled to the thermally-insulated storage container to supply liquid air to an interior of the thermally-insulated container.
 11. The refrigerated storage trailer of claim 10, wherein the liquid air refrigeration system includes a tank configured to store liquid air therein, and a conduit system having a first end portion coupled to the tank and a second end portion positioned within the interior of the thermally-insulated compartment.
 12. The refrigerated storage trailer of claim 11, wherein the liquid air refrigeration system further include a plurality of spray heads coupled to the second end portion of the conduit system.
 13. The refrigerated storage trailer of claim 11, wherein the conduit system includes a plurality of valves configured to control the flow of the liquid air from the tank to the thermally-insulated compartment.
 14. The refrigerated storage trailer of claim 11, further comprising a plurality of flow rate sensors configured to measure the rate of flow of the liquid air through the conduit system
 15. The refrigerated storage trailer of claim 10, further comprising a control system electrically coupled to liquid air refrigeration system to control the flow rate of liquid air into the interior of the thermally-insulated container.
 16. The refrigerated storage trailer of claim 15, further comprising a temperature sensor positioned within the interior of the thermally-insulated storage container, the temperature sensor configured to monitor the temperature within the interior of the thermally-insulated storage container, wherein the temperature sensor is electrically coupled to the control system, and wherein the control system is configured to adjust the rate of flow of the liquid air from the liquid air tank based upon the temperature sensed by the temperature sensor.
 17. A method of refrigerating a storage container comprising: providing a source of pressurized liquid air; injecting the liquid air from the source through a spray head into the storage container; and controlling the flow rate of the liquid air from the source.
 18. The method of claim 17, wherein controlling the flow rate includes monitoring a temperature of an interior of the storage container and adjusting the flow rate of the liquid air from the source based on the monitored temperature.
 19. The method of claim 17, wherein controlling the flow rate includes monitoring the flow rate of liquid air from the source and adjusting the flow rate of the liquid air from the source based on the monitored flow rate.
 20. The method of claim 17, further comprising determining if the temperature within the storage container is within a predetermined temperature range and generating a flow rate control signal in response thereto.
 21. The method of claim 20, further comprising changing the flow rate of the liquid air from the source in response to the flow rate control signal.
 22. A liquid air refrigeration system for a thermally-insulated storage container comprising: a liquid air refrigeration system; and a liquid air control system electrically coupled to the liquid air refrigeration system, the control system comprising (i) a processing unit, and (ii) a memory unit electrically coupled to the processing unit, the memory unit having stored therein a plurality of instructions which, when executed by the processing unit, causes the processing unit to: (a) operate the liquid air refrigeration system so as to advance liquid air from a liquid air storage tank to a thermally-insulated interior of a trailer, (b) determine if the temperature within the thermally-insulated interior of the trailer is within a predetermined temperature range and generating a flow rate signal in response thereto, and (c) change the flow rate of the liquid air from the liquid air storage tank to the thermally-insulated interior of the trailer in response to the flow rate signal. 